1. Field of the Invention
The present invention relates to an anvil cylinder for use in a processing machine which, when subjecting a sheet to processing operations such as punching after subjecting the same to printing, can prevent the sheet from being stained with ink and, more particularly, to an anvil cylinder for use in a processing machine which is suitable for being used to subject a corrugated board sheet to printing, ruling and punching so as to make a packing case.
2. Description of the Prior Art
Conventionally, in a processing machine for a corrugated board, a multiplicity of corrugated board sheets are stocked in the form of laminated or stacked sheets, the lowermost sheet being delivered from a sheet feeding unit to a printing unit in which the sheet is printed in one color, or in two or more colors. Subsequently, the sheet is fed to a creaser slotter unit in which the sheet is subjected to ruling. Subsequently, the sheet is fed into a rotary die cutter unit so as to be subjected to punching such as that for making a finger engagement bore. The ink which is applied to the sheet in the printing unit is of a quick-drying type. The feeding and conveying of the sheet to each processing unit, however, have in recent years been effected at high speed so as to cause an increase in the rate of operation. For this reason, the sheet was frequently punched, after having been printed, by a rotary die cutter in a state wherein the ink has not yet been dried up sufficiently. As a result, the ink was transferred from the non-dried printed surface of the corrugated board sheet onto the outer periphery of the anvil cylinder. The ink thus transferred thereonto was further transferred onto another succeeding sheet as a result of punching the same in a state wherein that ink has not yet been dried up. In consequence, the succeeding sheet was stained with the ink. In the prior art, transfer of ink from the sheet to the anvil cylinder and vice versa thus occur repeatedly each time the punching is carried out. This furthers the stain of the sheet with ink, resulting in a degradation of the product quality.